Cogeneration Power Plant
Saint John's operates a co-generation Power Plant which heats and cools all buildings on the main campus (excluding Flynntown), while producing approximately one-fourth (1/4) of the electricity consumed on campus. Co-generation means there are two uses for the steam which is produced in the boilers: the boilers generate steam at high pressure - this high-pressure steam passes through generators which produce electricity. The generators, in turn, exhaust steam at a low pressure which is then distributed around to campus to heat the facilities or, in the summer time, the low pressure steam is sent to the steam-absorption chillers which produce chilled water for cooling the facilities. Having two uses for the steam which is produced is what makes it economical for Saint John's to produce electricity - if we have no heating or cooling demand, it is more economical to purchase electricity. This is known as thermal demand.
While the Power Plant generates approximately one-fourth (1/4) of the electricity consumed on campus, its capability is much greater - allowing the power plant, in the short term, to carry the majority of the campus should our outside source of electricity be disrupted. However, operating at that level longer-term is not efficient or economical, because the corresponding thermal demand is lacking.
In addition to heating, cooling, and electrical generation, the Power Plant operates the domestic water system, including the water treatment facility, the water heaters, the water softeners, the wells, pumps, and water towers.